“猎户座”嬗变：从乘员探测飞行器到多用途载人飞船

2011年7月,美国将其依赖了30年之久的航天飞机送进了博物馆。在今后数年内,美国将只能租用俄罗斯的“联盟”飞船将航天员送往国际空间站。对于NASA来说,摆脱这种境地的一天已经变得可以预见,因为航天飞机的接任者——“猎户座”多用途载人飞船已经在“破茧”当中。     

《地心引力》科幻影片的传奇力作

太空科技为影片保驾护航《地心引力》在北美一经上映便吸引了众多的观众,他们被片中太空“搁浅者”的经历深深触动。这是一场视觉的盛宴,导演卡隆用极尽逼真的镜头将太空探索的艰险表现的淋淋尽致：航天飞机、     

ATV的“传奇人生”

2008年3月9日凌晨,伴随着隆隆的巨响,欧洲首艘自动转移飞行器（ATV）搭乘“阿里安”5火箭冲破法属圭亚那库鲁航天中心阴沉的小雨,成功发射,开启了6个月的太空之旅,     

来自西昌卫星发射中心的传奇故事

抢建2号工位上世纪八十年代末两颗＂澳星＂发射的合同是在大推力捆绑式火箭和发射工位均处于图纸设计阶段签订的。按照美国休斯公司要求,我国必须在16个月内建成一座现代化发射塔,并成功进行一次大推力火箭飞行试验。     

基于马尔可夫链的含有检测次数约束条件的唐检测器

针对可变驻留次数唐检测器由于驻留次数不定可能导致的单次检测次数已过多,但仍不能满足上/下行计数器值k=A或k=0退出条件的问题,提出一种对单次检测次数设置门限进行约束的方法来避免此种情况发生。将唐检测器建模为齐次马尔可夫链,利用齐次马尔可夫链中的首达时间与迟早概率等定义进行分析,得到含有检测次数约束的唐检测器检测性能公式。仿真结果表明,只要检测次数门限选择合理,可以在检测性能不受影响的情况下通过限制单次检测次数有效控制直接序列扩频信号的捕获验证时间。     

小白和小箭：50年前的传奇飞行

1960年8月19日11点44分07秒,拜科努尔发射场发射了＂东方＂号运载火箭,将重量为4,600千克的＂第二艘卫星式飞船＂送入轨道,在舱内的弹射容器内有两只狗狗,它们的名字分别叫做“小白”和“小箭”。     

一名女性志愿者的自述

中国选拔的第二批航天员中,将首次出现女性航天员的身影。女性航天员的选拔不同于男性航天员,没有现成的经验可以借鉴。在探索女性航天员选拔方法和标准过程中,有一个鲜为人知的群体在默默地奉献着——她们就是女性志愿者。仝飞舟正是其中之一,她向我们讲述了自己参加各种实验的经历和感受。     

高技派建筑的适用技术观

目前,高技派建筑得到广泛认可.高技派建筑在经过对技术的纯粹化的追求后,在技术不断发展的今天,高技派建筑师回归到对人文精神、地域性的关注上,使高技派建筑在信息技术时代焕发出新的生命力.本文论述了高技派建筑的适用技术观,通过分析揭示了高技派建筑的适用技术观对于建筑师的启示.     

高技派建筑的适用技术观

目前,高技派建筑得到广泛认可。高技派建筑在经过对技术的纯粹化的追求后,在技术不断发展的今天,高技派建筑师回归到对人文精神、地域性的关注上,使高技派建筑在信息技术时代焕发出新的生命力。本文论述了高技派建筑的适用技术观,通过分析揭示了高技派建筑的适用技术观对于建筑师的启示。     

从苏珊·巴斯奈特文化翻译观论桂林旅游景区公示语英译

公示语作为一种特殊的交际语言形式,具有指示性、提示性、限制性和强制性等四种功能,而旅游景区公示语除了具有公示语的功能外,还以特有的语言特色和交际功能为国内外游客的生活和旅游带来便利。论文对比了中英公示语的语言特色,以苏珊.巴斯奈特的文化翻译观为指导,综合论述了桂林景区公示语的翻译错误,并提出相应的翻译对策,旨在提高桂林旅游景区公示语的质量,使其充分发挥作用。     

Tides and the evolution of planetary habitability

Tides raised on a planet by the gravity of its host star can reduce the planet's orbital semi-major axis and eccentricity. This effect is only relevant for planets orbiting very close to their host stars. The habitable zones of low-mass stars are also close in, and tides can alter the orbits of planets in these locations. We calculate the tidal evolution of hypothetical terrestrial planets around low-mass stars and show that tides can evolve planets past the inner edge of the habitable zone, sometimes in less than 1 billion years. This migration requires large eccentricities (>0.5) and low-mass stars ( less or similar to 0.35 M(circle)). Such migration may have important implications for the evolution of the atmosphere, internal heating, and the Gaia hypothesis. Similarly, a planet that is detected interior to the habitable zone could have been habitable in the past. We consider the past habitability of the recently discovered, approximately 5 M(circle) planet, Gliese 581 c. We find that it could have been habitable for reasonable choices of orbital and physical properties as recently as 2 Gyr ago. However, when constraints derived from the additional companions are included, most parameter choices that indicate past habitability require the two inner planets of the system to have crossed their mutual 3:1 mean motion resonance. As this crossing would likely have resulted in resonance capture, which is not observed, we conclude that Gl 581 c was probably never habitable.     

SETI in the light of cosmic convergent evolution

Theodosius Dobzhansky, one of the founding fathers of the modern evolutionary synthesis, once famously stated that “nothing makes sense in biology except in the light of evolution”. Here it will be argued that nothing in astrobiology makes sense except in the light of “Cosmic Convergent Evolution” (CCE). This view of life contends that natural selection is a universal force of nature that leads to the emergence of similarly adapted life forms in analogous planetary biospheres. Although SETI historically preceded the rise of astrobiology that we have witnessed in the recent decade, one of its main tenets from the beginning was the convergence of life on a cosmic scale toward intelligent behavior and subsequent communication via technological means. The question of cultural convergence in terms of symbolic exchange, language and scientific capabilities between advanced interstellar civilizations has been the subject of ongoing debate. However, at the core of the search for extraterrestrial intelligence lies in essence a biological problem since even post-biological extraterrestrial intelligences must have had an origin based on self-replicating biopolymers. Thus, SETI assumes a propensity of the Universe towards biogenesis in accordance with CCE, a new evolutionary concept which posits the multiple emergence of life across the Cosmos. Consequently, we have to wonder about the biophilic properties the Universe apparently exhibits, as well as to try to find an encompassing theory that is able to explain this “fine-tuning” in naturalistic terms. The aims of this paper are as follows: 1) to emphasize the importance of convergent evolution in astrobiology and ongoing SETI research; 2) to introduce novel and biology-centered cosmological ideas such as the “Selfish Biocosm Hypothesis” and the “Evo Devo Universe” as valuable arguments in theorizing about the origin and nature of extraterrestrial intelligence and 3) to synthesize these findings within an emerging post-biological paradigm on which future SETI efforts may be founded.     

Role of the ionosphere for the atmospheric evolution of planets

We have synthesized current understanding, mainly observations, with regard to ion escape mechanisms to space from the ionosphere and exosphere of Titan and Earth-type planets, with the intent to provide an improved input for models of atmospheric evolution on early Earth and Earth-type planets and exoplanets. We focus on the role of the ionosphere and its non-linear response to solar parameters, all of which have been underestimated in current models of ancient atmospheric escape (4 billion years ago). Factors that have been overlooked include the following: (1) Much larger variation of O(+) outflow than H(+) outflow from the terrestrial ionosphere, depending on solar and geomagnetic activities (an important consideration when attempting to determine the oxidized state of the atmosphere of early Earth); (2) magnetization of the ionopause, which keeps ionospheric ions from escaping and controls many other escape processes; (3) extra ionization by, for example, the critical ionization velocity mechanism, which expands the ionosphere to greater altitudes than current models predict; and (4) the large escape of cold ions from the dense, expanded ionosphere of Titan. Here we offer, as a guideline for quantitative simulations, a qualitative diagnosis of increases or decreases of non-thermal escape related to the ionosphere for magnetized and unmagnetized planets in response to changes in solar parameters (i.e., solar EUV/FUV flux, solar wind dynamic pressure, and interplanetary magnetic field).     

Formation of nucleobases from formamide in the presence of iron oxides: implication in chemical evolution and origin of life

Simple compounds like HCN, which have one C and one N, are proposed as the probable precursors for biomonomers. Formamide, a hydrolysis product of HCN, is known as the precursor of various biologically important compounds, for example, nucleobases (purines and pyrimidines). In this paper, we report our results on the synthesis of nucleobases, adenine, cytosine, purine, 9-(hydroxyacetyl) purine, and 4(3H)-pyrimidinone from formamide, using iron oxide (hematite) and oxide hydroxides (goethite and akaganeite) as a catalyst. Goethite and hematite produced purine in higher yield. The products formed were characterized by high-performance liquid chromatography and electrospray ionization mass spectrometry techniques. Results of our study reveal that iron oxides might have worked as efficient prebiotic catalysts.     

A model for the evolution of the on-orbit man-made debris environment

A model for the evolution of the low Earth orbit man-made debris population is presented and the results of several test cases discussed. Debris sources include normal operations in space, explosions occurring on spacecraft in orbit, and collisions between objects in orbit; the stochastic occurrence of these deposition events is modeled using Monte Carlo techniques. A technique for discriminating between objects populating long-life vs rapid-decay orbits is discussed and applied to the analysis of debris contributions from collisions of comparable sized objects. In varying degrees, each of the cases presented indicate there is cause for concern for spacecraft and space operations from the 1990s onward-man-made debris will play a role which may vary from presenting a considerable hazard to certain operations or certain spacecraft to effectively prohibiting the use of certain spaceccraft or space operations.     

Recent advances in chemical evolution and the origins of life

This paper discusses the already 60 year old ideas of Oparin and Haldane, who suggested that the first forms of life were anaerobic, heterotrophic bacteria coming from chemical abiotic synthesis of organic compounds.     

Survey of mission evolution and flexibility in the Space Shuttle program

Given the diversity of missions it has accomplished and the myriad of adaptations it has undergone, the US Space Shuttle is widely regarded as a highly flexible space vehicle. With the Shuttle’s upcoming 2011 retirement, it is instructive to survey the history of this vehicle’s flexibility for the insights it can provide to the design and characterization of flexibility in future space systems. Data are presented on the evolution of mission requirements over time for 120 missions performed by the Space Shuttle over a period of some 27 years. Distinct trends in the time domain – as well as their causes – are identified and discussed, and early manifest plans from 1982 serve as a confirmation that these trends were not originally anticipated. Eight examples are then presented of engineering modifications that allowed the Shuttle to adapt and accommodate these requirement changes. Several additional instances of Shuttle flexibility are explored, such as post-Columbia disaster modification, upgrade programs and derived vehicles, and one case in which flexibility was inhibited by an early design decision.     

Observations on the evolution of satellite launch volume and cyclicality in the space industry

Satellites have been rightly described as the lifeblood of the entire space industry and the number of satellites ordered or launched per year is an important defining metric of the industry's level of activity, such that trends and variability in this volume have significant strategic impact on the space industry. Over the past 40+ years, hundreds of satellites have been launched every year. Thus an important dataset is available for time series analysis and identification of trends and cycles in the various markets of the space industry. This article reports findings of a study for which we collected data on over 6000 satellites launched since 1960 on a yearly basis. We grouped the satellites into three broad categories – defense and intelligence, science, and commercial satellites – and identified and discussed the main trends and cyclical patterns for each of these. Institutional customers (defense and intelligence, and science) accounted for over two-thirds of all satellites launched within our time period (1960–2008), and, in the 1960s and 1970s, they accounted for 90% and 73.5%, respectively. A fair conclusion from this data is that the space industry was enabled by, and grew because of the institutional customers, not commercial market forces. However, when the launch data is examined more closely, a growing influence of the commercial sector is noticeable. Over the past two decades communication satellites accounted for roughly half of all launches, thus reflecting an important shift in the space industry in which the commercial sector is playing an equal role (on a launch volume basis) to that of the institutional market. Cyclical patterns in the satellite launch volume over the past decade are separately discussed before we sum up with a conclusion.     

Rotational evolution of planetary systems under the action of gravitational and magnetic perturbations

Dynamics of planets around other stars that demonstrate a variety of possible characteristics is of interest from the point of view of realization of new scenarios of evolution which have not been realized in the Solar System. We consider the rotational evolution of exoplanets under the action of gravitational perturbations and magnetic disturbances using the methods of quality analysis and theory of bifurcation of multiparametric differential equations that describe evolution of non-resonant rotation of a dynamically symmetric planet magnetized along its symmetry axis. We analyze 64 phase portraits describing the evolution of angular momentum vector L for all possible values of planet parameters. The values of parameters are determined for the case when the direct rotation of a planet is changed for its retrograde rotation.     

The role of mud volcanoes in the evolution of Hecate Tholus Volcano on the surface of Mars

Hecate Tholus Volcano has undergone numerous changes in its history of evolution. Further, the phenomena occurring on the surface of this volcano endow us with a remarkable perspective of recent martian geological changes. In the vicinity of this volcano cone, most of the lava is covered with a thick layer of loose sediments (probably clay). The presence of such sediments at the base of the volcano cone has led to the formation of several major landslides. Moreover, liquid water flow on the volcano cone has created a myriad of radial channels. The formation of such structures on the cone of a volcano is only plausible as a result of eruption of a mud volcano from its crater. Besides, the constant discharge of mud-like materials as well as hot water from the volcano paves the way for the growth and evolution of hydrothermal organisms.